Big Marsh is a Low vegetation located in Grenville, Ontario and has an elevation of 104 meters.

• Latitude: 44° 51' 35'' North   (decimal: 44.8597222)
• Longitude: 75° 53' 29'' West   (decimal: -75.8913888)
• Topography Feature Category: Low vegetation
• Geographical Feature: Marsh
• Canadian Province/Territory: Ontario
• Elevation: 104 meters
• Location: Grenville
• Atlas of Canada Locator Map: Big Marsh
• GPS Coordinate Locator Map: Big Marsh Lat/Long